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11 records – page 1 of 2.

An Exploratory Study of Composite Cross-Laminated Timber (CCLT) Made from Bamboo and Hemlock-fir Mix

https://research.thinkwood.com/en/permalink/catalogue2411
Year of Publication
2019
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
PSL (Parallel Strand Lumber)
Application
Wood Building Systems

Block Shear Testing of CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2624
Year of Publication
2011
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Pirvu, Ciprian
Wang, Brad
Lum, Conroy
Organization
FPInnovations
Year of Publication
2011
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesive
Block Shear Test
Failure
Language
English
Research Status
Complete
Summary
A study was conducted with the primary objective of examining the efficacy of a standard block shear test method to assess the bond quality of cross-laminated timber (CLT) products. The secondary objective was to examine the effect of pressure and adhesive type on the block shear properties of CLT panels. The wood material used for the CLT samples was Select grade nominal 25 x 152-mm (1 x 6-inch) Hem-Fir. Three adhesive types were evaluated under two test conditions: dry and vacuum-pressure-dry (VPD), the latter as described in CSA standard O112.10. Shear strength and wood failure were evaluated for each test condition. Among the four properties evaluated (dry and VPD shear strength, and dry and VPD wood failure), only the VPD wood failure showed consistency in assessing the bond quality of the CLT panels in terms of the factors (pressure and adhesive type) evaluated. Adhesive type had a strong effect on VPD wood failure. The different performance levels of the three adhesives were useful in providing insights into how the VPD block shear wood failure test responds to significant changes in CLT manufacturing parameters. The pressure used in fabricating the CLT panels showed a strong effect on VPD wood failure as demonstrated for one of the adhesives. VPD wood failure decreased with decreasing pressure. Although dry shear wood failure was able to detect the effect of pressure, it failed to detect the effect of adhesive type on the bond quality of the CLT panels. These results provide support as to the effectiveness of the VPD block shear wood failure test in assessing the bond quality of CLT panels. The VPD conditioning treatment was able to identify poor bondline manufacturing conditions by observed changes in the mode of failure, which is also considered an indication of wood-adhesive bond durability. These results corroborate those obtained from the delamination test conducted in a previous study (Casilla et al. 2011). Along with the delamination test proposed in an earlier report, the VPD block shear wood failure can be used to assess the CLT bond quality. Although promising, more testing is needed to assess whether the VPD block shear wood failure can be used in lieu of the delamination test. The other properties studied (shear strength and dry wood failure), however, were not found to be useful in consistently assessing bond line manufacturing quality.
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Checking in CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2625
Year of Publication
2011
Topic
Moisture
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Lum, Conroy
Pirvu, Ciprian
Wang, Brad
Organization
FPInnovations
Year of Publication
2011
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Moisture
Keywords
Panels
Testing Methods
Surface Checks
Moisture Content
Gaps
Language
English
Research Status
Complete
Summary
A study was conducted with the primary objective of gathering information for the development of a protocol for evaluating the surface quality of cross-laminated timber (CLT) products. The secondary objectives were to examine the effect of moisture content (MC) reduction on the development of surface checks and gaps, and find ways of minimizing the checking problems in CLT panels. The wood materials used for the CLT samples were rough-sawn Select grade Hem-Fir boards 25 x 152 mm (1 x 6 inches). Polyurethane was the adhesive used. The development of checks and gaps were evaluated after drying at two temperature levels at ambient relative humidity (RH). The checks and gaps, as a result of drying to 6% to 10% MC from an initial MC of 13%, occurred randomly depending upon the characteristics of the wood and the manner in which the outer laminas were laid up in the panel. Suggestions are made for minimizing checking and gap problems in CLT panels. The checks and gaps close when the panels are exposed to higher humidity. Guidelines were proposed for the development of a protocol for classifying CLT panels into appearance grades in terms of the severity of checks and gaps. The grades can be based on the estimated dimensions of the checks and gaps, their frequency, and the number of laminas in which they appear.
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Composite Cross Laminated Timber (CCLT) Made with Engineered Wood Products (EWP) and Hardwood

https://research.thinkwood.com/en/permalink/catalogue1578
Year of Publication
2016
Topic
Design and Systems
Cost
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
General Application
Author
Grandmont, Jean-Frédéric
Wang, Brad
Year of Publication
2016
Country of Publication
Austria
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
General Application
Topic
Design and Systems
Cost
Mechanical Properties
Keywords
Dimensional Stability
SPF
Birch
Aspen
Maple
Equilibrium Moisture Content
Delamination
Bond Line
Manufacturing
Language
English
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1723-1730
Summary
North American cross laminated timber is currently made of softwood lumber following the guidelines of the ANSI/APA PRG-320 manufacturing standard. In this study, the potential of manufacturing CLT panels using various hardwood species and engineered wood products (EWP) was investigated for their compatibility and the impact...
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Cross-Laminated Timber (CLT) in China: A State-of-the-Art

https://research.thinkwood.com/en/permalink/catalogue2108
Year of Publication
2019
Topic
Market and Adoption
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Li, Hao
Wang, Brad
Wei, Peixing
Wang, Libin
Publisher
Nanjing Forestry University
University of New Brunswick
Cellulose and Renewable Materials Division of Chinese Chemical Society
Year of Publication
2019
Country of Publication
Canada
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Market and Adoption
Keywords
China
Language
English
Research Status
Complete
Series
Journal of Bioresources and Bioproducts
ISSN
2369-9698
Online Access
Free
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Delamination Testing of CLT Panels: An Exploratory Study

https://research.thinkwood.com/en/permalink/catalogue2626
Year of Publication
2011
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Casilla, Romulo
Pirvu, Ciprian
Wang, Brad
Organization
FPInnovations
Year of Publication
2011
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Adhesive
Bond Quality
Delamination Test
Strength
Language
English
Research Status
Complete
Summary
A study was conducted with the primary objective of examining the efficacy of delamination test using cylindrical core specimens to assess the bond quality of cross laminated timber (CLT) products. A prototype coring drill bit was fabricated to prepare a cylindrical-shaped specimen, the height of which corresponds to the full thickness of the CLT panel. A secondary objective was to examine the effect of pressure, adhesive type, number of plies, and specimen shape on the delamination resistance of CLT panels. The wood material used for the CLT samples was Select grade nominal 1 x 6-inch Hem-Fir boards. Examples of three adhesive types were evaluated, which were designated as A, B, and C. The delamination tests used were as described in CAN / CSA O122-06 and EN 302-2. Cylindrical specimen extracted as core was found satisfactory as a test specimen type for use in delamination testing of CLT product. Its efficacy was comparable to that of a square cross-section specimen. The former is recommended as it can be extracted from thicker panels and from any location in the panel. It would also be more convenient to plug the round hole. Adhesive type had a strong effect on delamination resistance based on the two delamination tests used. Adhesive A exhibited the greatest delamination resistance, followed in decreasing order, by adhesives C and B. It should be noted that no effort was made to find the optimum CLT manufacturing parameters for each type of adhesive. Therefore the relative rankings of the adhesives tested may not be representative. However, for the purposes of this study, the different performance levels from the three adhesives are useful in providing insight into how the proposed delamination test responds to significant changes in CLT manufacturing parameters. Pressure used in fabricating the CLT panel showed a strong effect on delamination resistance as demonstrated for one of the adhesives. Delamination resistance decreased with decreasing pressure. The effect of the number of plies in the CLT panel was dependent upon the type of adhesive, and this was probably related to the adhesive’s assembly time characteristic. These results provide support as to the effectiveness of delamination test in assessing the moisture durability of CLT panels. It was able to differentiate the performance in delamination resistance among different types of adhesives, and able to detect the effect of manufacturing parameters such as pressure and increased number of plies in CLT construction. The test procedure described in CAN / CSA O122-06 appears to be reasonable in the delamination resistance assessment of CLT panels for qualification and quality control testing. Based on the results of the study along with some background information and guidelines, delamination requirements for CLT panels are proposed. The permitted delamination values are greater than those currently specified for laminated and fingerjoined lumber products. This is in recognition of the higher bond line stresses when bonded perpendicular laminations (i.e. CLT) are exposed to the delamination wetting and drying cycles, as opposed to parallel laminations (i.e. glulam or fingerjoints).
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Development of Cross-Laminated Timber (CLT) Products from Stress Graded Canadian Hem-Fir

https://research.thinkwood.com/en/permalink/catalogue2595
Year of Publication
2020
Topic
Design and Systems
Material
CLT (Cross-Laminated Timber)
Author
Wei, Peixing
Wang, Brad
Li, Zhong
Ju, Ronghua
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Design and Systems
Keywords
Hem-Fir
Modulus of Elasticity
Modulus of Rupture
Stress-Graded Lumber
Language
English
Research Status
Complete
Series
Wood Research
Summary
To explore the feasibility of hem-fir for CLT products, this work addressed the exploratory and pilot plant studies of hem-fir cross-laminated timber (CLT) products through mechanical tests. The hem-fir lumber was procured and then stress-graded based on dynamic modulus of elasticity (MOE). The resulted 5-ply prototype CLT products were then tested non-destructively and 3-ply pilot plant hem-fir CLT was tested destructively. The results showed that bending performance of hem-fir CLT panel can be predicted. Considering cost-competitiveness and end applications of hem-fir CLT products, the panel structure can be optimized based on the stress-graded data of hem-fir lumber.
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New Attributes and Economic Analyses of Composite CLT and Value-Added Appearance-Based CLT

https://research.thinkwood.com/en/permalink/catalogue354
Year of Publication
2014
Topic
Cost
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
General Application
Author
Grandmont, Jean-Frédéric
Wang, Brad
Organization
FPInnovations
Year of Publication
2014
Country of Publication
Canada
Format
Report
Material
CLT (Cross-Laminated Timber)
LSL (Laminated Strand Lumber)
LVL (Laminated Veneer Lumber)
Application
General Application
Topic
Cost
Mechanical Properties
Keywords
Delamination
Hardwood
Softwood
Structural Composite Lumber
Economic Analysis
Structural Properties
Aesthetic Properties
Language
English
Research Status
Complete
Summary
The objective of this study was to examine new attributes and conduct economic analyses for composite CLT (CCLT) and value-added appearance-based CLT products manufactured with varying substitution of softwood lumber with structural composite lumber (SCL) and hardwood lumber. Incentives for including such materials could be aesthetic, structural and economic.
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Performance Evaluation of Phenol Formaldehyde Resin-Impregnated Veneers and Lamminated Veneer Lumber

https://research.thinkwood.com/en/permalink/catalogue1444
Year of Publication
2012
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Application
General Application
Author
Wang, Brad
Chui, Ying Hei
Publisher
Society of Wood Science and Technology
Year of Publication
2012
Country of Publication
United States
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Application
General Application
Topic
Mechanical Properties
Keywords
Mountain Pine Beetle
Lodgepole Pine
Resin Impregnation
Modulus of Elasticity
Phenol Formaldehyde
Dimensional Stability
Hardness
Bending Strength
Bending Modulus
Shear Strength
Language
English
Research Status
Complete
Series
Wood and Fiber Science
Summary
For the past decade, mountain pine beetle infestation in British Columbia, Canada, has substantially changed wood characteristics of vast amounts of the lodgepole pine (Pinus contorta) resource. Resin impregnation is one method that could improve the properties of the beetle-affected wood...
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11 records – page 1 of 2.